JP2000006369A - Thin film printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a printing unevenness of a thin film by providing a printing protrusion on a letterpress arranged on an outer periphery of a cylindrical printing roller, and providing a dummy printing protrusion to be brought into pressure contact with a printing surface before the protrusion, thereby alleviating an impact in the case of bringing the protrusion into contact with the printing surface. SOLUTION: On a letterpress 7, a printing protrusion 71 having a pattern shape to be formed and a dummy printing protrusion 72 for alleviating an impact in the case of bringing the protrusion 71 into pressure contact with a material to be printed by bringing the protrusion 72 into pressure contact with the material before the protrusion 71 is brought into pressure contact with the material. The protrusion 72 is, for example, provided at the letterpress 7 so as to be brought into pressure contact with a position out of a thin film printing range of a printing surface to be cut out after the thin film printing. Accordingly, even if a film thick distribution occurs at this position according to its impact, no influence is affected. Thus, the thin film having small printing unevenness can be printed, and a glass board having a uniform and good thin film can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film printing apparatus for printing a thin film on a printing surface, and more particularly to an apparatus for reducing uneven printing of a thin film.

[0002]

2. Description of the Related Art A TV image is a moving image having a fine and halftone. When displaying this TV image, high resolution,
High-speed response, multi-step display, high contrast, high reliability,
The most advanced technology such as colorization is required. In this regard,
The quality of the TV image displayed on the CRT is very good.

In recent years, liquid crystal (display) devices that can be reduced in weight in the trend of increasing the area of a display image have been receiving attention. Recently, a nematic liquid crystal has been provided by providing a switching element for each pixel. Active research has been made mainly on a TV image display method using a directly driven active matrix type liquid crystal element.

Here, the TFT method is considered to be the most excellent as a switching element incorporated in such a liquid crystal element. However, the complexity of the element manufacturing process, the number of steps, and the like are major obstacles to an increase in area. I have.

On the other hand, a display device in which transmitted light is controlled in combination with a polarizing element utilizing the refractive index anisotropy of ferroelectric liquid crystal molecules has been proposed by Clark and Lagerwall. (JP-A-56-107216, U.S. Pat.
No. 7924).

Here, this ferroelectric liquid crystal generally has a non-helical chiral smectic C phase (SmC ^* ) or H phase (SmH ^* ) in a specific temperature range, and is added in this state. Taking one of a first optically stable state and a second optically stable state in response to an electric field;
In addition, it has a property of maintaining the state when no electric field is applied, that is, it has bistability, has a quick response to a change in the electric field, and is expected to be widely used as a high-speed and storage-type display element. From this function, application to a large-screen, high-definition display device using a simple matrix driving method is expected.

By the way, various thin films such as an alignment film are formed on a liquid crystal element. In the case of a ferroelectric liquid crystal in particular, a very thin alignment film of 50 to 300 ° is required for controlling the alignment. In addition, as a method of forming such a thin film such as an alignment film, a cylindrical printing roller provided with a relief on the outer peripheral surface is rotated, and a printing projection of the relief is pressed against a printing surface of a glass substrate. Flexographic printing of a thin film, in which an undiluted solution of a thin film attached to a printing projection is transferred to a printing surface of a glass substrate and the thin film is printed.

[0008]

However, in such a conventional thin film printing apparatus that prints a thin film by flexographic printing, when the printing projection first hits the glass substrate, the printing projection of the glass substrate firstly contacts the glass substrate. An impact occurs at the pressed part. Then, due to this impact, the transfer amount of the undiluted solution of the thin film to the glass substrate increases, whereby the film thickness in this portion increases, and printing unevenness occurs.

For example, if the stock solution of the alignment film is polyamic acid and a polyimide thin film having a thickness of about 200.degree. It becomes about 40 to 50 ° thicker than the thickness, and the deviation = (σ / Ave) ×
100 (%) exceeds the 6.0% required for the ferroelectric liquid crystal.

[0010] When the film thickness distribution of the thin film is generated on the alignment film or the like due to the printing unevenness, there is a problem that, for example, in a ferroelectric liquid crystal display or the like, color unevenness or switching failure occurs.

As another thin-film printing apparatus, for example, as disclosed in Japanese Patent Application Laid-Open No. 63-217324, a pressure-adjusting convex portion is formed on the side of the printing convex portion so as to be able to press each position on the printing surface. Although some attempts are made to make the pressure substantially constant, even with such a configuration, it is not possible to absorb the impact when the printing projection first hits.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a thin film printing apparatus capable of reducing uneven printing of a thin film.

[0013]

According to the present invention, there is provided a thin-film printing apparatus for printing a thin film on a printing surface by using a printing convex portion of a relief plate arranged on an outer peripheral surface of a cylindrical printing roller. In this case, a dummy printing convex portion that is pressed against the printing surface is provided earlier.

Further, the present invention is characterized in that the dummy printing projection is provided on the relief printing plate so as to be pressed against a position outside the thin-film printing area of the printing surface.

Further, as in the present invention, a dummy printing projection is provided on a relief plate arranged on the outer peripheral surface of a cylindrical printing roller, and the dummy printing projection is pressed against the printing surface prior to the printing projection. In addition, the impact when the printing projection hits the printing surface is reduced.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a basic configuration of a thin film printing apparatus according to the present embodiment. Referring to FIG. 1, reference numeral 1 denotes a developing color table for uniformly holding a thin film forming material (hereinafter referred to as ink) on the surface. The developing color table 1 can be moved up and down by a lifting mechanism (not shown) and a motor 5. Spin (rotation) is possible. The coloring table 1 is made of flat metal, glass, or a polymer material, and has a disk shape having a larger area than a pattern to be formed.

Reference numeral 2 denotes an ink supply unit for discharging ink to the developed color table 1. The ink supply unit 2 moves to the position shown by the broken line when the developed color table 1 is at the lower position (broken line). The ink K is discharged from the pressurized tank 3 to the center of the display table 1 in a fixed amount. here,
This ink K has a low viscosity and has a viscosity of several cp to 2 cp.
000 cp and is composed of a mixture of a resin or a resin precursor and a solvent.

After the ink K is ejected, the ink supply unit 2 is slid to the position shown by the solid line. In addition, the exhibition color table 1 uses the ink K
Is ejected and then rises and comes out of the spin cup 4. After leaving the spin cup 4 in this manner, the motor 5 spins for a set time and a set number of revolutions so that the ejected ink K is evenly spread on the surface. After the ink K is evenly spread on the surface in this way, the spread color table 1 is raised to a predetermined position and fixed.

On the other hand, in the figure, reference numeral 6 denotes a plate cylinder which is a printing roller, and a relief plate 7 is arranged on the outer peripheral surface of the plate cylinder 6. Here, the plate cylinder 6 rises to a predetermined position in a state where the ink K is spread evenly on the surface, moves above the fixed developing table 1, and then rotates.

When the plate cylinder 6 rotates as described above,
The letterpress 7 arranged on the outer peripheral surface of the plate cylinder 6 comes into contact with the surface of the color developing table 1 so that the ink is transferred to the letterpress surface. The relief printing plate 7 has a pattern shape to be formed, and is formed of rubber such as butyl rubber or a nylon resin, or photosensitive rubber or photosensitive resin.

Further, after the ink has been transferred to the relief printing plate surface in this way, the plate cylinder 6 moves above the printing material 8 which transfers the ink to the surface, and then rotates. Then, when the plate cylinder 6 rotates in this manner, the relief printing plate 7 having the ink transferred to the surface thereof is pressed against the surface of the printing medium 8, the ink is transferred to the printing medium surface, and a thin film is printed. Has become. Here, as the printing medium 8, a glass substrate or the like having a smooth surface is used. In FIG. 1, reference numeral 9 denotes a stage for supporting the printing medium 8.

FIG. 2 is a plan view of the relief printing plate 7,
As shown in the figure, the relief printing plate 7 has a printing projection 71 having a pattern shape to be formed and a dummy printing projection 72. Here, the dummy print projection 72 is
This is for reducing the impact when the printing projection 71 presses against the printing medium 8 before the printing projection 71 presses against the printing medium 8. Note that in FIG.
Reference numeral 3 denotes an alignment mark for aligning the center of the plate with the center of the substrate when disposing the relief plate 7 on the outer peripheral surface of the plate cylinder 6.

In this way, the dummy printing projections 72 reduce the impact when the printing projections 71 are pressed against the printing medium 8, so that a thin film with less printing unevenness can be printed. Accordingly, a glass substrate having a uniform and favorable thin film can be formed, and a highly reliable and high quality liquid crystal element and a liquid crystal device having the same can be obtained.

When the dummy print projection 72 comes into pressure contact with the printing medium 8, an impact is generated.
For example, since the relief plate 2 is provided on the relief plate 7 so as to be pressed against a position out of the thin-film printing area of the printing surface which is cut off after the thin-film printing, the impact causes a film thickness distribution of the thin film at this position. There is no effect.

Next, a description will be given of a thin film forming operation in the thin film forming apparatus thus configured.

First, as shown in FIG. 1, the spread color table 1 is moved to the lower position (broken line), and thereafter the ink supply unit 2 is moved to the position shown by broken line and added to the center of the spread color table 1. A predetermined amount of ink K is discharged from the pressure tank 3. Thereafter, the ink supply unit 2 slides to the position shown by the solid line, and the developed color table 1 rises and goes out of the spin cup 4.

Next, the developed color table 1 that has come out of the spin cup 4 is spun by the motor 5 for a set time and a set number of revolutions, and the ejected ink K is spread evenly on the surface. Thereafter, the developed color table 1 is raised to a predetermined position and fixed.

Next, the plate cylinder 6 rises from the position shown in the figure to a predetermined position as shown in FIG. 3, moves to a position above the fixed developing table 1, and then rotates. As a result, the relief plate 7 arranged on the outer peripheral surface of the plate cylinder 6 is pressed against the surface of the color developing table, and the ink K on the surface of the color developing table is moved to the surface of the relief plate 7,
Specifically, the printing projection 71 and the dummy printing projection 72 (FIG. 2)
See).

Next, after the ink is transferred to the surface of the relief printing plate 7, the plate cylinder 6 is moved from the position shown in FIG. 4 to above the printing material 8 as shown in FIG. This allows
The relief printing plate 7 is pressed against the printing medium 8 to transfer the ink K to the surface of the printing medium 8 to form a thin film.

Here, during this printing, before the printing projection 71 presses against the printing medium 8, the dummy printing projection 72 presses against the printing medium 8. The impact at the time of pressing against is reduced.

By reducing the impact when the printing projection 71 is pressed against the printing medium 8 by the dummy printing projection 72 in this manner, the thickness of the pressed portion does not increase, and the deviation = (σ / (Ave) × 100 (%) can be obtained as a thin film having a substantially uniform film thickness distribution within 6.0%.

Next, an example of this embodiment will be described.

(First Embodiment) First, 1
Using a glass substrate having a thickness of 1 mm, Al was formed on this glass substrate by sputtering at a thickness of about 1500 ° to provide a monitor for measuring the film thickness by an ellipsometer. Next, a polyimide alignment film was flexographically printed on the glass substrate by using a thin film printing apparatus according to the present embodiment using a solvent-resistant resin plate: APR plate, and baked to form about 200 mm.

In this embodiment, a printing solution (ink) for forming a polyimide alignment film was prepared by Hitachi Chemical Co., Ltd.
Ultra-high purity NMP and nB of 99.5% or more
C: weight ratio LQ1800: NMP: nBC = 9.86:
A solution diluted to 50.14: 40.00 was used. In addition, the exhibition color table 1 is set at 1000 rpm for 20 seconds.
After the rotation of c, the printing solution was spread almost uniformly on the developing table. Further, the letterpress used was the one shown in FIG. 2 described above.

FIG. 5 shows the result of measurement of the thin film printed and fired by the ellipsometer in the case of using a relief plate provided with a dummy printing projection as is apparent from FIG. The thickness of the portion where the printing convex portion of the relief printing plate first comes into pressure contact with the glass substrate does not increase, and the deviation = (σ / Av
e) A thin film having a substantially uniform film thickness distribution of x100 (%) within 6.0% was obtained.

(Second Embodiment) First, 1
Using a glass substrate having a thickness of 1 mm, Al was formed on this glass substrate by sputtering at a thickness of about 1500 ° to provide a monitor for measuring the film thickness by an ellipsometer. Next, a polyimide alignment film was flexographically printed on the glass substrate by using a thin film printing apparatus according to the present embodiment using a solvent-resistant resin plate: APR plate, and baked to form about 200 mm.

In this embodiment, a printing solution (ink) for forming a polyimide alignment film was prepared by Hitachi Chemical Co., Ltd.
Ultra-high purity NMP and nB of 99.5% or more
C: weight ratio LQ1800: NMP: nBC = 9.86:
A solution diluted to 50.14: 40.00 was used.

Further, the printing table 1 was rotated at 1000 rpm for 20 seconds, and the printing solution was spread almost uniformly on the printing table. Further, in the present embodiment, the letterpress is shown in FIG.
The following was used. In the same figure, reference numeral 74 denotes a dummy printing convex portion, and the dummy printing convex portion 74 is also pressed against the relief plate 7 so as to be pressed against a position out of the thin film printing range of the printing surface which is cut off after the thin film printing. Is provided.

FIG. 7 shows the results of measurement of the thin film printed and baked in this way by ellipsometry. As can be seen from FIG. 7, the case where a relief plate provided with a dummy printing projection is used. The thickness of the portion where the printing convex portion of the relief printing plate first comes into pressure contact with the glass substrate does not increase, and the deviation = (σ / Av
e) A thin film having a substantially uniform film thickness distribution of x100 (%) within 6.0% was obtained.

Next, a comparative example will be described.

(Comparative Example) First, the printing medium 8 was 1 mm
Using a thick glass substrate, Al was deposited on this glass substrate by sputtering at a thickness of about 1500 ° to provide a monitor for film thickness measurement by an ellipsometer. Next, a polyimide alignment film was flexographically printed on the glass substrate by using a thin film printing apparatus according to the present embodiment using a solvent-resistant resin plate: APR plate, and baked to form about 200 mm.

In this comparative example, as a printing solution (ink) for forming a polyimide alignment film, L was manufactured by Hitachi Chemical Co., Ltd.
Ultra-high purity NMP and nB of 99.5% or more
C: weight ratio LQ1800: NMP: nBC = 9.86:
A solution diluted to 50.14: 40.00 was used. The exhibition color table is 20 seconds at 1000 rpm.
The printing solution was rotated to spread the printing solution almost uniformly on the color developing table.

Further, in this comparative example, a letterpress having no dummy printing portion was used as shown in FIG.

FIG. 9 shows the results of measurement of the thin film printed and fired by the ellipsometer in this manner. As is apparent from FIG. 9, a relief plate having no dummy print projection was used. In this case, the thickness of the portion where the printing convex portion of the relief printing plate is first pressed against the glass substrate becomes high, and the deviation = (σ /
(Ave) × 100 (%) exceeded 8.0%, and a uniform film thickness distribution was not obtained.

[0046]

As described above, according to the present invention, a dummy printing projection is provided on a relief plate arranged on the outer peripheral surface of a cylindrical printing roller, and the dummy printing projection is formed before the printing projection. By contacting the printing surface with the printing surface, it is possible to reduce the impact when the printing projection hits the printing surface, and it is possible to reduce the printing unevenness of the thin film.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a thin film printing apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a relief plate used in the thin film printing apparatus.

FIG. 3 is a diagram illustrating a part of a thin film printing operation of the thin film printing apparatus.

FIG. 4 is a view for explaining another part of the thin film printing operation of the thin film printing apparatus.

FIG. 5 is a diagram showing a film thickness distribution measurement result according to a first example of the present embodiment.

FIG. 6 is a plan view of a letterpress used in a second example of the present embodiment.

FIG. 7 is a view showing a film thickness distribution measurement result according to the second embodiment.

FIG. 8 is a plan view of a relief plate used in a comparative example of the present embodiment.

FIG. 9 is a view showing a result of measuring a film thickness distribution according to the comparative example.

[Description of Signs] 1 Developing color table 2 Ink supply unit 5 Rotating motor 6 Body plate 7 Letterpress 71 Printing projection 72, 74 Dummy printing projection 8 Printed object K ink

Claims (2)

[Claims] 1. A thin-film printing apparatus that prints a thin film on a printing surface by a printing ridge of a relief plate disposed on an outer peripheral surface of a cylindrical printing roller, wherein the printing plate is provided on the printing surface earlier than the printing projection portion. A thin-film printing apparatus comprising a dummy printing projection to be pressed against. 2. The thin-film printing apparatus according to claim 1, wherein the dummy printing projection is provided on the relief printing plate so as to be pressed against a position outside the thin-film printing range on the printing surface.